An Investigation of the Kinetic Processes Influencing Mercury Emissions from Sand and Soil Samples of Varying Thickness
- Jason L. Quinones and
- Anthony Carpi *
Mercury flux from HgCl2–treated sand and untreated soil samples of varying thickness (0.5–15 mm) were measured in dark and light under a Teflon dynamic flux chamber. Mean emissions over a 5.5-d sampling period showed an increase with depth for sand samples between 0.5 and 2 mm, but increasing depth above 2 mm had no effect. First-order kinetic models showed strong goodness of fit to the data and explained a high degree of variability in the emissions profile of all sand samples (R 2 = 0.70–0.98). Soil samples showed an initial emissions peak that was not correlated with depth, suggesting a very shallow process at work. However, longer-term “baseline” emissions, measured as mean emissions between Days 4.5 and 5.5, did show a relationship with depth. First-order kinetic models showed good fit for soil samples up to 4 mm thick (R 2 = 0.66–0.91); however, thicker samples did not show a consistent fit to first- or second-order kinetic models (1° R 2 = 0.00–0.46; 2° R 2 = 0.00–0.54). The data suggest that mercury emissions from soil samples may follow a multicomponent model for which more than one component is affected by incident radiation.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © 2011.